**Course Title:** Modern C++ Programming: Mastering C++ with Best Practices and Advanced Techniques **Section Title:** Data Structures and Algorithms in C++ **Topic:** Solve real-world problems using STL containers and algorithms. (Lab topic) ## Introduction In this lab, you will apply your knowledge of STL containers and algorithms to solve real-world problems. You will learn how to use these data structures and algorithms to efficiently solve complex problems, making you a more productive and effective programmer. ### Objectives * Understand how to apply STL containers and algorithms to real-world problems * Learn how to analyze problems and identify the most suitable STL containers and algorithms to use * Gain practical experience in using STL containers and algorithms to solve complex problems ### Problem 1: Student Database Suppose you are a teacher and you want to manage a database of your students. You want to store their names, ages, and grades. You also want to be able to search for students by name or age, and sort them by grade. **Task:** Use an `std::map` to store the student database, where the key is the student's name and the value is a `std::tuple` containing the student's age and grade. Implement functions to: * Add a new student to the database * Search for a student by name or age * Sort the students by grade **Example Code:** ```cpp #include <map> #include <tuple> #include <algorithm> std::map<std::string, std::tuple<int, double>> studentDatabase; void addStudent(const std::string& name, int age, double grade) { studentDatabase[name] = std::make_tuple(age, grade); } void searchStudentByName(const std::string& name) { auto it = studentDatabase.find(name); if (it != studentDatabase.end()) { std::cout << "Student found: " << name << ", Age: " << std::get<0>(it->second) << ", Grade: " << std::get<1>(it->second) << std::endl; } else { std::cout << "Student not found: " << name << std::endl; } } void searchStudentByAge(int age) { for (const auto& student : studentDatabase) { if (std::get<0>(student.second) == age) { std::cout << "Student found: " << student.first << ", Age: " << age << ", Grade: " << std::get<1>(student.second) << std::endl; } } } void sortStudentsByGrade() { std::vector<std::pair<std::string, std::tuple<int, double>>> vec(studentDatabase.begin(), studentDatabase.end()); std::sort(vec.begin(), vec.end(), [](const auto& a, const auto& b) { return std::get<1>(a.second) > std::get<1>(b.second); }); for (const auto& student : vec) { std::cout << "Student: " << student.first << ", Age: " << std::get<0>(student.second) << ", Grade: " << std::get<1>(student.second) << std::endl; } } int main() { addStudent("John", 20, 85.0); addStudent("Jane", 21, 90.0); addStudent("Bob", 20, 80.0); searchStudentByName("John"); searchStudentByAge(20); sortStudentsByGrade(); return 0; } ``` ### Problem 2: Shopping Cart Suppose you are building an e-commerce website and you want to implement a shopping cart feature. You want to store the items in the cart, along with their prices and quantities. **Task:** Use an `std::vector` to store the items in the cart, where each item is a `std::tuple` containing the item's name, price, and quantity. Implement functions to: * Add an item to the cart * Remove an item from the cart * Calculate the total cost of the items in the cart **Example Code:** ```cpp #include <vector> #include <tuple> std::vector<std::tuple<std::string, double, int>> cart; void addItemToCart(const std::string& itemName, double price, int quantity) { cart.emplace_back(itemName, price, quantity); } void removeItemFromCart(const std::string& itemName) { cart.erase(std::remove_if(cart.begin(), cart.end(), [&](const auto& item) { return std::get<0>(item) == itemName; }), cart.end()); } double calculateTotalCost() { double totalCost = 0.0; for (const auto& item : cart) { totalCost += std::get<1>(item) * std::get<2>(item); } return totalCost; } int main() { addItemToCart("Apple", 1.99, 2); addItemToCart("Banana", 0.99, 3); addItemToCart("Orange", 2.49, 1); std::cout << "Total cost: " << calculateTotalCost() << std::endl; removeItemFromCart("Apple"); std::cout << "Total cost after removing Apple: " << calculateTotalCost() << std::endl; return 0; } ``` ### Conclusion In this lab, you have applied your knowledge of STL containers and algorithms to solve real-world problems. You have learned how to use these data structures and algorithms to efficiently solve complex problems, making you a more productive and effective programmer. **Key Takeaways:** * Use STL containers and algorithms to solve real-world problems * Analyze problems and identify the most suitable STL containers and algorithms to use * Use `std::map` to store data with key-value pairs * Use `std::vector` to store data with variable size * Use `std::tuple` to store data with multiple values **External Resources:** * [C++ Standard Library](https://en.cppreference.com/w/) * [STL Containers and Algorithms](https://www.geeksforgeeks.org/stl-containers-and-algorithms-in-cpp/) **Leave a Comment/Ask for Help:** If you have any questions or need help with any of the problems, please leave a comment below.